Method for making a stabilized absorbent composite

ABSTRACT

A method for forming and stabilizing an absorbent composite web includes conforming a first web onto a forming surface having a plurality of raised nubs having upper surfaces. The first web defines a plurality of bond areas corresponding to those portions of the first web overlying the upper surfaces of the nubs. The method further includes depositing absorbent material onto the first web to form a unitary absorbent core having a plurality of holes therein. The method further includes joining a second web to the first web at the bond areas to form an absorbent composite web. The unitary absorbent core is positioned between the first web and the second web. The first web and the second web are bonded together through the holes in the absorbent core. The method further includes removing the absorbent composite web from the forming surface.

BACKGROUND OF THE INVENTION

The present invention relates to stabilized absorbent composites andmethods for making stabilized absorbent composites. The absorbentcomposites of the present invention are suitable for incorporation intoa variety of disposable absorbent articles such as, for example,diapers, children's training pants, adult incontinence pads andgarments, menstrual pads, bed pads, surgical drapes, and the like.

Conventional absorbent composites have traditionally been made ofcellulosic fluff or other fibrous materials. Many have also includedsuperabsorbent particles dispersed within the fibrous materials.However, many of these traditional absorbent composites have sufferedfrom structural breakdowns during use, including, for example, cracking,separating, wadding, and/or “roping.” These problems are generallyundesirable and may cause discomfort for the wearer and/or may limit theperformance of the absorbent composite.

Additionally, some conventional absorbent composites have exhibitedundesirable “gel-on-skin” wherein some of the superabsorbent particlesescape the absorbent composite and stick to the wearer during use. Thisproblem may be worse with absorbent articles having a higher amount ofsuperabsorbent material as a percentage of the total absorbent materialweight.

Various attempts to prevent or minimize structural breakdowns andsuperabsorbent losses have included, for example, densifying thecellulosic fluff, adding adhesives or other binding agents to theabsorbent material, wrapping the absorbent material in nonwovens ortissues, point bonding the absorbent core, aperturing the absorbentcore, needling the absorbent core, placing the superabsorbent materialin pockets or discrete layers, among others. However, there still existsa need for a simple and efficient way to stabilize absorbent compositesto minimize or eliminate structural breakdowns and superabsorbentlosses.

SUMMARY OF THE INVENTION

In response to the discussed need, the present invention provides amethod for forming and stabilizing an absorbent composite web. Themethod includes conforming a first web onto a forming surface. The firstforming surface has a plurality of raised nubs having upper surfaces.The first web defines a plurality of bond areas corresponding to thoseportions of the first web overlying the upper surfaces of the nubs. Themethod further includes depositing absorbent material onto the first webto form a unitary absorbent core having a plurality of holes therein.The method further includes joining a second web to the first web at thebond areas to form an absorbent composite web, wherein the unitaryabsorbent core is positioned between the first web and the second web.The first web and the second web are bonded together through the holesin the absorbent core. Finally, the method includes removing theabsorbent composite web from the forming surface.

In various embodiments, the method may further include applying adhesiveto the second web before joining the second web to the first web and/ormay include pressing the second web against the first web while thefirst web is conformed to the forming surface to effectuate the joiningof the second web to the first web.

In various embodiments, the method may further include joining the firstweb and the second web using ultrasonic bonding, thermal bonding, orpressure bonding.

In various embodiments, the first web may be drawn to the formingsurface via vacuum forces and the forming surface may be a drum former.

In various embodiments, the nubs may have a height of 1.5 to 6 mm and asurface area of 1 to 25 mm².

In various embodiments, the absorbent material may includesuperabsorbent particles and cellulose fluff fibers. For example, theunitary absorbent core may include 30 to 90 percent superabsorbentparticles and 70 to 10 percent cellulose fluff fibers by weight.

In various embodiments, portions of the absorbent composite web thatinclude the unitary absorbent core may have a thickness of less than 6mm.

In various embodiments, the method may further include scarfing theabsorbent core to expose the bond areas before joining the second web tothe first web.

In various embodiments, the first web and the second web may be tissuewebs and may be joined with adhesive. In various embodiments, the firstweb and the second web may be nonwoven webs and may be joined byadhesive bonding, ultrasonic bonding, thermal bonding, or pressurebonding.

In another embodiment, the present invention provides a method forforming an absorbent composite web that includes conforming a firsttissue web onto a forming surface via vacuum forces. The forming surfacehas a plurality of raised nubs having upper surfaces and wherein thefirst tissue web defines a plurality of bonding areas corresponding tothose portions of the first tissue web overlying the upper surfaces ofthe nubs. The method further includes depositing superabsorbent andcellulose fluff onto the first tissue web to form a unitary absorbentcore having a plurality of holes therein. The method further includesapplying adhesive to a second tissue web, pressing the second tissue webagainst the first tissue web to join the first and second tissue webs atthe bonding areas to form an absorbent composite web. The unitaryabsorbent core is positioned between the first tissue web and the secondtissue web. The first tissue web and the second tissue web are bondedtogether through the holes in the unitary absorbent core. The methodfurther includes removing the absorbent composite web from the formingsurface.

In various embodiments, the method further includes scarfing the unitaryabsorbent core to remove substantially all absorbent material from thebond areas.

In various embodiments, the absorbent material may includesuperabsorbent particles and cellulose fluff fibers. For example, theunitary absorbent core may include 30 to 90 percent superabsorbentparticles and 70 to 10 percent cellulose fluff fibers by weight.

In various embodiments, portions of the absorbent composite web thatinclude the unitary absorbent core may have a thickness of less than 6mm.

In another embodiment, the present invention provides a method forforming an absorbent composite web that includes conforming a firstnonwoven web onto a forming surface via vacuum forces. The formingsurface has a plurality of raised nubs having upper surfaces and thefirst nonwoven web defines a plurality of bond areas corresponding tothose areas of the first nonwoven web overlying the upper surfaces ofthe nubs. The method further includes depositing superabsorbent andcellulose fluff onto the first nonwoven web to form a unitary absorbentcore, scarfing the absorbent core to remove substantially all absorbentmaterial from the bond areas thereby further defining a plurality ofholes in the unitary absorbent core, joining the second nonwoven web tothe first nonwoven web at the bond areas using adhesive bonding,ultrasonic bonding, thermal bonding, or pressure bonding to form anabsorbent composite web. The,unitary absorbent core is positionedbetween the first nonwoven web and the second nonwoven web. The firstnonwoven web and the second nonwoven web are bonded together through theholes in the unitary absorbent core. The method further includesremoving the absorbent composite web from the forming surface.

In various embodiments, the absorbent material may includesuperabsorbent particles and cellulose fluff fibers. For example, theunitary absorbent core may include 30 to 90 percent superabsorbentparticles and 70 to 10 percent cellulose fluff fibers by weight.

In various embodiments, portions of the absorbent composite web thatinclude the unitary absorbent core may have a thickness of less than 6mm.

In various embodiments, the method further includes separating theabsorbent composite web into discrete absorbent composites and placingthe discrete absorbent composites between a bodyside liner and anoutercover to form an absorbent article.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 representatively illustrates an exemplary method and apparatus ofthe present invention.

FIG. 2 representatively illustrates a perspective view of a portion ofan exemplary method and apparatus of the present invention.

FIG. 3 representatively illustrates a portion of FIG. 2 designated bybracket 3.

FIG. 4 representatively illustrates a portion of FIG. 2 designated bybracket 4.

FIG. 5 representatively illustrates a portion of the method andapparatus of the present invention.

FIG. 6 representatively illustrates a cross-sectional view of the methodand apparatus of FIG. 5 taken along the line 6-6.

FIG. 7 representatively illustrates an exemplary absorbent article ofthe present invention.

FIG. 8 representatively illustrates the absorbent article of FIG. 7 inthe laid flat condition with the side contacting the wearer facing theviewer.

FIG. 9 representatively illustrates an exemplary absorbent composite ofthe present invention.

FIG. 10 representatively illustrates the portion of the absorbentcomposite of FIG. 9 delineated by box 10.

FIG. 11 representatively illustrates a cross sectional view of FIG. 10taken along the line 11-11.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 representatively illustrates an exemplary method and apparatus ofthe present invention useful for forming absorbent composite webs. Theabsorbent composite webs of the present invention may be utilized invarious absorbent articles, such as, for example, disposable diapers,adult incontinence articles, children's training pants, feminine hygienearticles, bandages, and the like.

One embodiment of the method of the present invention is illustratedgenerally at 20 and includes conforming a first web 22 onto a formingsurface 24 having a plurality of nubs 34 (FIG. 2) protruding therefrom,depositing absorbent material 26 onto the first web 22 to form a unitaryabsorbent core web 28, and joining a second web 30 in facing relationwith the first web 22 to form an absorbent composite web 32 wherein theabsorbent core web 28 is located between the first web 22 and the secondweb 30.

The method 20 and apparatus of the invention can include a formingchamber 44 through which the forming surface 24 is movable. The formingchamber 44 has an appointed entrance portion 46, and an appointed exitportion 48. A fiber source, such as provided by a fiberizer 50, can beconfigured to provide fibrous material into the forming chamber 44, anda vacuum generator or other vacuum source can be configured to providean operative, relatively lower pressure, vacuum condition in avacuum-commutator duct system 52. In the illustrated configuration, thefiberizer 50 can be provided by a rotary hammer mill or a rotatablepicker roll. Other fiberizers may also be employed, as desired.

As the forming surface 24 enters and then traverses through the formingchamber 44, the component materials of the absorbent core web 28, suchas, the fibrous material, are operatively carried or transported by anentraining air stream that is drawn through the first web 22 and theforming surface 24. Typically, the low pressure, vacuum generatingsystem is constructed and arranged to produce the desired airflowthrough the first web 22 and the forming surface 24. Such vacuum formingsystems are well known in the art.

Other component materials for producing the absorbent core web 28 mayalso be delivered into the forming chamber 44. For example, particles orfibers of superabsorbent material may be introduced into the formingchamber 44 by employing conventional mechanisms, such as pipes,channels, spreaders, nozzles, and the like, as well as combinationsthereof. In the representatively shown configuration, the superabsorbentmaterial can be delivered into the forming chamber 44 by employing anoperative conduit and nozzle system 54. The illustrated orientation ofthe delivery conduit 54 is exemplary, and it should be readilyappreciated that any operative orientation of the delivery conduit andnozzle system 54 may be employed. The fibers, particles and otherdesired absorbent core materials may be entrained in any suitablegaseous medium.

The stream of air-entrained absorbent materials 26 can pass through theforming chamber 44 for deposition onto the first web 22 which overliesthe forming surface 24. The forming chamber 44 can serve to direct andconcentrate the air-entrained absorbent materials 26, and to provide adesired velocity profile in the air-entrained stream of absorbentmaterials 26. Typically, the forming chamber 44 is supported by suitablestructural members, which together form a support frame for the formingchamber. The frame may be anchored and/or joined to other suitablestructural components, as necessary or desirable.

The forming surface 24 can be provided by any suitable mechanism. In therepresentatively shown configuration, the forming surface 24 is providedby a forming drum 56. Other conventional techniques for providing theforming surface 24 may also be employed. For example, the formingsurface 24 may be provided by an endless forming belt. Forming beltsystems for producing fibrous webs are well known in the art. Examplesof such forming belt systems are available from the Paper ConvertingMachine Company, a business,having offices located in Green Bay, Wis.,U.S.A.; and from Curt G. Joa Incorporated, a business having officeslocated in Sheboygan Falls, Wis., U.S.A.

In the representatively shown configuration, a forming drum systemoperatively provides the moving forming surface 24. More particularly,the moving foraminous forming surface 24 can be provided by an outerperipheral surface region of a rotatable forming drum 56. The formingdrum 56 is rotatable in a selected direction of rotation, and can berotated by employing a drum drive shaft that is operatively joined toany suitable drive mechanism (not shown). For example, the drivemechanism can include an electric or other motor which is directly orindirectly coupled to the drive shaft. While the shown arrangementprovides a forming drum that is arranged to rotate in acounter-clockwise direction, it should be readily apparent that theforming drum may alternatively be arranged to rotate in a clockwisedirection.

A suitable forming drum and forming system are taught in U.S. Pat. No.6,630,096 to Venturino et al. issued Oct. 7, 2003, the entirety of whichis incorporated herein by reference to the extent that it is consistent(i.e., not in conflict) herewith.

In the illustrated embodiment, under the influence of the vacuumgenerating source, a conveying air stream is drawn through the first web22 and the foraminous forming surface 24 into the interior of theforming drum 56, and is subsequently passed out of the drum through thevacuum supply conduit 58. As the air-entrained absorbent materials 26impinge on the first web 22, the air component is passed through thefirst web 22 and the forming surface 24 and the absorbent materials 26are retained on the first web 22 to form a nonwoven unitary absorbentcore web 28 thereon. The illustrated embodiments show a continuouslyformed unitary absorbent core web 28 formed on the first web 22.However, those skilled in the art will readily appreciate that discreteabsorbent cores may alternatively be formed on the first web 22 suchthat a space exists between the absorbent cores. Therefore, where theterm “absorbent core web” or “unitary absorbent core web” is usedherein, the term “discrete absorbent core” or “discrete unitaryabsorbent core” is equally applicable in various embodiments. Suitablemethods for forming discrete absorbent cores are disclosed in U.S.patent application Ser. No. 11/215876 to Wisneski et al. entitled“Method and Apparatus for Making Absorbent Article With Core Wrap” andfiled on Aug. 30, 2005, the entirety of which is incorporated herein byreference to the extent that it is consistent (i.e., not in conflict)herewith.

Optionally, a scarfing system may be positioned at the exit region 48 ofthe forming chamber 44. The scarfing system can include a scarfingchamber 60 and a scarfing roll 62 which is positioned within thescarfing chamber. The scarfing roll can abrade excess absorbent material26 from the absorbent core web 28, and the removed fibers can betransported away from the scarfing chamber 60 with a suitable dischargeconduit, as is well known in the art. The removed absorbent material 26may, for example, be recycled back into the forming chamber 44 or thefiberizer 50, as desired. Additionally, the scarfing roll can rearrangeand redistribute the web material along the longitudinalmachine-direction of the web and/or along the lateral cross-direction ofthe web.

The rotatable scarfing roll may be operatively connected and joined to asuitable shaft member, and may be driven by a suitable drive system (notshown). The scarfing roll system can provide a conventional trimmingmechanism for removing or redistributing any excess, z-directionalthickness of the absorbent core web 28 that has been deposited on thefirst web 22. The surface of the scarfing roll can be adjusted toprovide a desired contour along the scarfed surface of the absorbentcore web 28. The scarfing roll can, for example, be configured toprovide a substantially flat surface along the scarfed surface of theabsorbent core web 28. The scarfing roll can optionally be configured toprovide a non-flat surface. The scarfing roll 62 is disposed in spacedadjacent relationship to the forming surface 24, and the forming surface24 is translated past the scarfing roll. A conventional transportingmechanism, such as a suction fan (not shown) can draw the removedfibrous material away from the formed absorbent core web 28 and out fromthe scarfing chamber 60.

The scarfing roll 62 may be rotated in a direction which moves acontacting surface of the scarfing roll in a counter-direction that isopposite the movement direction of the absorbent core web 28.Alternatively, the scarfing roll 62 may be rotated in a co-directionthat is the same as the movement direction of absorbent core web 28. Ineither situation, the rotational speed of the scarfing roll 62 should besuitably selected to provide an effective scarfing action against thecontacted surface of the formed absorbent core web 28. In like manner,any other suitable trimming mechanism may be employed in place of thescarfing roll assembly to provide a cutting or abrading action to thelaid fibrous web by a relative movement between the fibrous web and theselected trimming mechanism. A suitable scarfing system is taught inU.S. Pat. No. 6,627,130 to Kugler et al. issued Sep. 30, 2003, theentirety of which is incorporated herein by reference to the extent thatit is consistent (i.e., not in conflict) herewith.

After formation of the absorbent core web 28, the second web 30 isoverlaid upon the absorbent core web 28 and the first web 22 while bothare conformed to the forming surface 24 and the nubs 34 (FIG. 2)protruding therefrom. The second web 30 is then joined to the first web22 while still conformed to the forming surface 24 and the nubs 34 toform the completed absorbent composite web 32. Subsequently, with therotation of the drum, the formed absorbent composite web 32 can beremoved from the forming surface 24. The removal operation may beprovided by the weight of the absorbent composite web 32, by centrifugalforce, by a positive air pressure, or by combinations thereof. Thepositive air pressure can be produced, for example, by a source ofcompressed air or a fan which generates a pressurized air flow thatexerts a force directed outwardly through the forming surface.

The portion of the forming surface 24 that is carrying the absorbentcomposite web 32 can be moved to an optional pressure blow-off zone ofthe forming drum system. In the blow-off zone, air can be introducedunder pressure and directed radially outwardly against absorbentcomposite web 32 on the portion of the forming surface that becomesaligned with the blow-off zone. The gas pressure can effect a readyrelease of the absorbent composite web 32 from the forming surface 24,and the absorbent composite web 32 can be removed from the formingsurface onto a suitable transport mechanism.

A web transporter can receive the absorbent composite web 32 from theforming drum 56, and convey the absorbent composite web 32 for furtherprocessing. In various embodiments, portions the absorbent composite web32, such as the first web 22 and/or the second web 30, may be folded toseal the edges of the absorbent core web 28.

Suitable web transporters can, for example, include conveyer belts,vacuum drums, transport rollers, electromagnetic suspension conveyors,fluid suspension conveyors, or the like, as well as combinationsthereof. As representatively shown, the web transporter can be providedby a system which includes the illustrated endless conveyor belt 64disposed about rollers 66. In a particular configuration of theinvention, a vacuum suction box 68 can be located below the conveyorbelt 64 to help remove the absorbent composite web 32 from the formingsurface 24. The vacuum box 68 opens onto the belt 64, and a suction ofair out of the vacuum box can draw an air flow through perforations inthe conveyor belt. This flow of air can, in turn, operate to draw theabsorbent composite web 32 away from the forming surface. The vacuum boxcan be employed with or without the use of a positive pressure in theblow-off zone.

With reference to FIG. 2, the forming surface 24 can be provided alongthe outer, cylindrical surface of the forming drum 56, and can extendalong the axial (cross-directional) and circumferential(machine-directional) dimensions of the forming drum. The structure ofthe forming surface 24 can be composed of an assembly, and can include aforaminous or otherwise porous member 70 which is operatively connectedand joined to the forming drum 56.

The porous forming member 70 can extend along the outer, circumferentialperiphery of the forming drum 56. The forming member 70 can be composedof any suitable porous material. The foraminous member 70 may include ascreen, a wire mesh, a hard-wire cloth, a perforated member, or thelike, as well as combinations thereof. In a particular aspect, theforaminous member can include a fluted member having open channels whichcan extend generally radially and can allow a substantially free flow ofair or other selected gas from the outward-side of the drum towards thecenter of the drum. The flutes or channels can have any desiredcross-sectional shape, such as circular, oval, hexagonal, pentagonal,other polygonal shape, or the like, as well as combinations thereof.Such honeycomb structures are well known in the art, and can be composedof various materials, such as plastic, metal, ceramics, and the like, aswell as combinations thereof. For example, suitable materials andstructures are available from Innovent, a business having officeslocated in Peabody, Mass., U.S.A.

In various embodiments, the radially outward surface of the flutedmember or other foraminous member 70 can be configured with a selectedsurface contour. The contoured surface regions of the foraminous member70 can be formed to have any operative shape. In various arrangements,the contour shape can be trapezoidal. Alternatively, the contour shapecan be domed or flat.

The forming surface 24, and particularly the porous member 70, caninclude a forming surface contour which is uniform or non-uniform alongits depth dimension. For example, the forming surface 24 can provide arelatively low-basis-weight region, and at least one relativelyhigh-basis-weight region, such as provided by pocket regions. In variousembodiments, at least one relatively high basis weight region can bepositioned along a medial region of the forming surface 24.Alternatively, at least one relatively high basis weight region can bepositioned along one or more other, non-medial regions of the formingsurface 24.

With reference to FIGS. 2, 3, 5 and 6, at least one side-masking member,such as provided by a side contour ring 72 can be disposed on theforaminous member 70. In various embodiments, the invention can includea cooperating system of side-masking members. As representatively shown,a pair of laterally opposed, side contour ring members 72 can beconfigured to extend circumferentially around the forming drum 56. In aparticular aspect, the contour rings 72 can be operatively attached andpositioned along laterally opposed, outboard edge regions of theforaminous member 70. The contour rings 72 can be joined and assembledto the forming surface 24 by employing conventional attaching ormounting mechanisms.

FIG. 2 representatively illustrates a perspective view of the first web22 conforming to a forming surface 24 with portions of the absorbentmaterial 26 and portions of the first web 22 cut away along line 84 toillustrate underlying details. FIG. 3 representatively illustrates amore detailed view of the portion of FIG. 2 designated by bracket 3 withthe absorbent material 26 removed to illustrate underlying details. FIG.4 representatively illustrates a more detailed view of the portion ofFIG. 2 designated by bracket 4.

Referring now to FIGS. 2 and 3, the forming surface 24 includes aplurality of raised nubs 34 having upper surfaces 36. In variousembodiments, the raised nubs 34 may also have side surfaces 38. Thefirst web 22 is conformed about the forming surface 24 and the pluralityof nubs 34. The first web 22 may be drawn down to the forming surface 24and around the nubs 34 via vacuum forces or the like. The first web 22overlies the forming surface 24 and the nubs 34 and defines a pluralityof bonding areas 40. The bonding areas 40 correspond to those portionsof the first web 22 overlying the upper surfaces 36 of the nubs 34.

As used herein, the terms “conform,” “conforming,” or derivativesthereof mean to give the same shape, outline, or contour to. Forexample, when the first web 22 is “conformed” to the forming surface 24,the first web 22 is generally in contact with most of the formingsurface 24 and at least the upper surfaces 36 of the nubs 34. See FIG. 6for an example of the first web 22 conforming to the forming surface 24and the nubs 34.

The nubs 34 may be formed out of a wide variety of different materials.For example, the nubs 34 may be formed out of plastic, metal, ceramin,or the like, or combinations thereof. Metallic nubs are advantageousbecause they are durable and have a relatively low coefficient offriction. An aluminum nub provided with polytetrafluorethylene or othersuitable release coating can be used to provide a durable and lowfriction nub.

The nubs 34 may be attached to the forming surface 24 by using anysuitable means such as, for example, fasteners, welding, adhesives, andthe like, and combinations thereof. Alternatively, the nubs 34 may beformed integrally with the forming surface 24. In various embodiments,the nubs 34 may be the heads of various fasteners, such as, for example,bolts or screws, or the like, having any suitable head, such as, hexheads, button heads, socket heads, cap heads, or the like, orcombinations thereof. For example, in some embodiments, the nubs 34 maybe bolts secured to the forming surface 24. The nubs 34 are illustratedas lying within the interior region of the forming surface whereby thenubs 34 will be completely circumscribed by the absorbent material 26deposited on the first web 22 overlying the forming surface 24. However,in various embodiments, the nubs 34 may be located at the edges of theforming surface whereby only a portion of one or more nubs 34 may becircumscribed by the absorbent material 26.

The illustrated nubs 34 do not include perforations or apertures oneither the side surfaces 38 or upper surfaces 36 of the nub 34 and,thus, process air is not pulled directly through the illustrated nubs34. It would be possible, however, for the nubs to include such openingson the side surface 38 to allow the process air to be removed therethough in addition to the remainder of the forming surface 24.

In various embodiments, the surface area of any individual nub 34 may be1 mm² (0.0015 in²) to 200 mm² (0.3 in²), 1 mm² (0.0015 in²) to 100 mm²(0.155 in²), or 1 mm² (0.0015 in²) to 25 mm² (0.03875 in²). In someembodiments, the surface area of any individual nub 34 may be less than200 mm², less than 100 mm², less than 90 mm², less than 80 mm², lessthan 70 mm², less than 60 mm², less than 50 mm², less than 40 mm², lessthan 30 mm², less than 20 mm², or less than 10 mm². In variousembodiments, the total nub surface area may be between about 1 to about33 percent, about 1 to about 25 percent, or less than about 10 percentof the total forming surface area. As used herein, the total nub surfacearea is the combined cross sectional area of the nubs at the base of thenubs where the nubs are attached to the forming surface. The totalforming surface area includes the area of the forming surface on whichthe absorbent material is deposited plus the total nub surface area.

In various embodiments, the nubs 34 may have any suitable height. Thenub height represents the perpendicular distance that the upper surface36 of the nubs 34 extends from the forming surface 24. In variousembodiments, the nubs 34 may have a height less than 10, less than 9,less than 8, less than 7, less than 6, less than 5, less than 4, lessthan 3, or less than 2 mm. In some embodiments, the nubs 34 may have aheight of 1 mm to 10 mm, 1 mm to 7 mm, or 1.5 mm to 6 mm.

The nubs 34 may have a variety of different shapes and/orconfigurations. For example, the cross section of the nubs 34 may definea circle, oval, star, diamond, rectangle, or any other geometric figure.In some embodiments, the nubs 34 may have an irregular cross sectionalshape or may be generally linear or arcuate. Furthermore, the crosssectional shape of the nubs 34 may vary over the height of the nubs 34.For example, the nubs 34 may be provided with a slight taper whereby theupper surface 36 of the nub 34 has an area which is less than the crosssectional area of the base of the nub at the point where the nub isattached to the forming surface 24. The inward taper of the sidesurfaces 38 may be in the range of between 0° to about 15°. For example,side surfaces may have an inward taper of approximately 5° or 7°.

Alternatively, the side surfaces 38 of the nubs 34 may be perpendicularto the forming surface 24, pitched slightly outward, or vary over theperimeter or height of the nub 34. For example, a, nub 34 could have aleading edge 74 which is perpendicular to the forming surface and atrailing edge 76 which is pitched slightly inward and thus have a pitchwhich varies over the perimeter of the nub 34. A nub 34 which isperpendicular near its base (i.e., has a 0° taper) but tapers inwardlynear its distal end would have a pitch which varies over the height ofthe nub 34. Thus, the nubs 34 may take a variety of different shapes.The configuration of the nubs 34, however, must account for theinteraction of the nub 34 and the first web 22 and the absorbent coreweb 28.

In some embodiments, the nubs 34 may have a circular shape. The nubs 34may have a diameter of 1 mm to 16 mm, 1 mm to 10 mm, or 1 mm to 5 mm. Insome embodiments the nubs 34 may have a diameter of less than 16 mm,less than 10 mm, or less than 5 mm. The pattern formed by the nubs 34 onthe forming surface 24 may be varied significantly.

Referring now to FIGS. 2 and 4, the method 20 furtherincludes-depositing absorbent material 26 onto the first web 22 to forma unitary absorbent core web 28 having a plurality of holes 41 formedtherein. The absorbent material 26 surrounds the bonding areas 40 whichoverlie the nubs 36 thereby defining the holes 41. The unitary absorbentcore web 28 defines lateral side edges 31. In embodiments with discreteabsorbent cores, the discrete absorbent cores further definelongitudinal end edges 80 (see FIG. 9). In various embodiments, thebonding areas 40 of the first web 22 are free of absorbent material 26or substantially free of absorbent material 26. In various embodiments,the bonding areas 40 may include some absorbent material 26 that isremoved prior to subsequent processing. In some embodiments, thescarfing roll 62 can optionally be configured to remove most or alldeposited absorbent material 26 from the bonding areas 40 of the firstweb 22.

As used herein, the term “unitary” means “undivided” and describes anabsorbent core wherein no portion of the absorbent core is completelydisconnected from any other portion. The unitary absorbent core includesa plurality of holes wherein a first sheet and a second sheet are bondedtogether through the plurality of holes to form an absorbent composite.In other words, a unitary absorbent core is a “sea” of absorbentmaterial with “islands” of bond points. In contrast, some prior artabsorbent cores formed discrete pockets of absorbent materialencapsulated between sheets that were connected together between thepockets to create a “sea” of bond areas with “islands” of absorbentmaterial.

Unitary absorbent cores can be formed discretely or can be formed aswebs. As used herein, the term “unitary absorbent core web” describes aseries of unitary absorbent cores directly connected together to form aweb. As used herein, the term “discrete unitary absorbent core”describes a unitary absorbent core that is formed such that it is notdirectly connected to another unitary absorbent core.

The method 20 further includes joining a second web 30 to the first web22 on upper surfaces 36 of the nubs 34 to form an absorbent compositeweb 32 upon the forming surface 24. FIG. 5 representatively illustratesa portion of the method 20 not seen in FIG. 2 wherein the second web 30is joined in facing relation to the first web 22 at bond points 45 toform the absorbent composite web 32. The bond points 45 correspond tothe bonding areas 40 of the first web 22. In various embodiments, thesecond web 30 may additionally be joined to the first web 22 at marginalareas 42. The marginal areas 42 are defined as the areas outboard of theabsorbent core lateral side edges 78 and the longitudinal end edges 80.

As used herein, the use of the term “join,” “joined,” “joining,” orvariations thereof in describing the relationship between two elementsmeans that the two elements can be connected together by heat sealing,ultrasonic bonding, adhesive bonding, thermal bonding, pressure bonding,stitching, or the like, or combinations thereof. Further, the twoelements can be joined directly together (i.e., touching), or may haveone or more elements interposed between them, all of which are suitablyconnected together.

In the illustrated embodiments, the absorbent core web 28 is formed as acontinuous web and therefore the marginal areas 42 extend beyond thelateral side edges 78 of the absorbent core web 28. However, thoseskilled in the art will readily appreciate that discrete absorbent coresmay be formed such that a space exists between subsequent absorbentcores. As such, the marginal areas 42 may therefore extend around theentire perimeter 29 of the absorbent core (FIG. 9). Suitable methods forforming discrete absorbent cores is disclosed in U.S. patent applicationSer. No. 11/215876 to Wisneski et al. entitled “Method and Apparatus forMaking Absorbent Article With Core Wrap” and filed on Aug. 30, 2005, theentirety of which is incorporated herein by reference to the extent thatit is consistent (i.e., not in conflict) herewith.

FIG. 6 representatively illustrates a cross sectional view of theabsorbent composite web 32 on the forming surface 24 taken along theline 6-6 of FIG. 5. The first web 22 is conformed to the forming surface24 and overlays the nubs 34 and the side contour rings 72 at themarginal area 42. The portions of the first web 22 overlying the uppersurfaces 36 of the nubs 34 define the bonding areas 40. The absorbentmaterial 26 is formed upon the first web 22 and surrounds the nubs 34 toform the unitary absorbent core web 28 having holes 41 therein. Theholes 41 are defined by the nubs 34. The bonding areas 40 of the firstweb 22 are exposed within the holes 41. The absorbent core web 28 alsoincludes a perimeter 29 defined in part by the side contour rings 72.The second web 30 is overlaid on the first web 22 and the unitaryabsorbent core web 28. The second web 30 is joined to the first web 22at the bonding areas 40 to form bond points 45. The second web 30 mayalso be joined to the first web 22 at the marginal areas 42. Therefore,the absorbent composite web 32 is stabilized because the first web 22and the second web 30 are joined together at bond points 45 which extendthrough holes 41 in the absorbent core web 28 located between the firstweb 22 and the second web 30.

The second web 30 may be joined to the first web 22 by any suitablemeans to form the absorbent composite web 32. In various embodiments,the second web 30 may be joined to the first web 22 at the bonding areas40 and/or the marginal areas 42 by adhesive bonding, ultrasonic bonding,thermal bonding, pressure bonding, and the like, and combinationsthereof to form the absorbent composite web 32. The joining at thebonding areas 40 results in bond points 45.

In some embodiments, the second web 30 may be joined to the first web 22by applying adhesive to the second web 30 before overlying the secondweb 30 in facing relation with the first web 22 and the unitaryabsorbent core web 28. The second web 30 may then be directly joined tothe bonding areas 40 of the first web 22 via the adhesive to form theabsorbent composite web 32 having bond points 45. In variousembodiments, the adhesive may be applied to the first web 22 and/or thesecond web 30 in any suitable pattern or covering any suitable surfacearea. For example, the adhesive pattern may include meltblown, swirl,slot coat, beads, or the like, or combinations thereof. The adhesive maybe applied across at least 50 percent, at least 60 percent, at least 70percent, at least 80 percent, or at least 90 percent of the surface areaof the first web 22 and/or the second web 30. The adhesive is preferablyapplied to at least those portions of the second web 30 that align withthe bonding areas 40 of the first web 22 to effectuate the joining ofthe webs 22 and 30 at the bonding areas 40 to form the bond points 45.

In various embodiments, adhesive may be applied to the first web 22, thesecond web 30, or both the first web 22 and the second web 30 before thesecond web 30 is overlaid upon the absorbent core web 28 and the firstweb 22. In various embodiments, the second web 30 may be pressed againstthe bonding areas 40 to effectuate a stronger joining at the bond points45 between the first web 22 and the second web 30 while on the formingsurface 24.

In various embodiments, the second web 30 may be joined to the first web22 at the marginal areas 42 to define a flange 43. The flange 43 mayextend beyond the perimeter 29 of the unitary absorbent core web 28 byany suitable distance. The flange 43 may be subsequently cut by anysuitable means into any suitable shape and suitable contour. Forexample, in some embodiments, the flange 43 may be cut using a diecutter, high pressure water cutter, or the like, and may be shaped tofollow the lateral side edges 78 of the unitary absorbent core web 28.In some embodiments, including the forming of discrete absorbent cores,the flange 43 may be generally shaped to follow the entire perimeter 29of the discrete absorbent core (FIG. 9).

In some embodiments, the marginal areas 42 of the first web 22 may befolded around the absorbent core web 28 and joined to the second web 30to seal the lateral edges 78 of the absorbent core web 28. In someembodiments, the marginal areas 42 of the second web 30 may be foldedaround the absorbent core web 28 and joined to the first web 22 to sealthe lateral edges 78 of the absorbent core web 28. In some embodiments,the flange 43 formed by the first web 22 and the second web 30 may befolded around the absorbent core web 28 and joined to first web 22and/or the second web 30. Any suitable means may be used to fold thefirst web 22, the second web 30, and/or the flange 43. For example,conventional folding boards, and the like, may be used. Suitable foldingmethods and apparatus are disclosed in U.S. patent application Ser. No.10/955,820 to Mischler et al., filed on Sep. 30, 2004, the entirety ofwhich is incorporated herein by reference to the extent that it isconsistent (i.e., not in conflict) herewith

The present invention advantageously forms holes 41 in the absorbentcore web 28 around the bonding areas 40. The first web 22 and the secondweb 30 are joined together through the holes 41 at the bonding areas 40to form bond points 45 while the first web 22 is conformed about thenubs 34 and the absorbent core web 28 is formed about the nubs 34thereby ensuring registration between the bonding areas 40 and the holes41. Furthermore, having both the hole formation step and the bondingstep occur on the same forming surface 24 allows the size of the hole 41to be very similar to the size of the bond point 45 in the bonding area40 because both are created by the same nub 34 while still engaged withthe nub 34. In other words, the bond points 45 cannot get out ofregistration with the holes 41.

In some embodiments, the first web 22 may provide the functions of boththe first web 22 and the second web 30. For example, the first web 22may define a forming section and a wrap section. The first web 22 may beprovided at a width substantially wider than the width of the absorbentcore web 28. The absorbent core web 28 may be formed on the formingsection of the first web 22 as described herein and the wrap section ofthe first web 22 may be folded and overlaid upon the absorbent core web28 and joined to the forming section as described herein to create theabsorbent composite web 32.

In various embodiments, the absorbent composite web 32 may be compressedor densified by any suitable means, such as, for example, passing theabsorbent composite web 32 through a fixed gap nip commonly referred toas debulking. Debulking the absorbent composite web 32 compresses andexpands the unitary absorbent core web 28 and reduces the size of theholes 41. Therefore, the size of the holes 41 approaches the size of thebond points 45 and results in minimally oversized holes 41 as comparedto the bond points 45.

In various embodiments, the first web 22 may be a tissue web, the secondweb 30 may be a tissue web, and the second web 30 may be joined to thefirst web 22 at the bonding areas 40 to form bond points 45 withadhesive or any other suitable means.

In various embodiments, the first web 22 may be a nonwoven web, thesecond web 30 may be a nonwoven web, and the second web 30 may be joinedto the first web 22 at the bonding areas 40 to form bond points 45 byadhesive bonding, ultrasonic bonding, pressure bonding, thermal bonding,or the like, or combinations thereof.

In various embodiments, the first web 22 and the second web 30 may beprovided by a similar material. Alternatively the first web 22 and thesecond web 30 may be provided by dissimilar materials. The first web 22may be adapted to face a user's body during use, and the second web 30may be adapted to face away from the user's body during use or the firstweb 22 may be adapted to face away from a user's body during use, andthe second web 30 may be adapted to face the user's body during use.

Various woven and nonwoven fabrics may comprise the first web 22 and/orthe second web 30. For example, the first web 22 and/or the second web30 may be composed of a meltblown or spunbonded web of polyolefinfibers. The first web 22 and/or the second web 30 may also be abonded-carded web composed of natural and/or synthetic fibers. The firstweb 22 and/or the second web 30 may be composed of a substantiallyhydrophobic material, and the hydrophobic material may, optionally, betreated with a surfactant, or otherwise processed, to impart a desiredlevel of wettability and hydrophilicity. Specifically, the first web 22and/or the second web 30 may be a nonwoven, spunbond-meltblown-spunbond,polypropylene fabric having a basis weight of about 5 to 30 gsm.

The first web 22 and/or the second web 30 may be stretchable, eitherelastically or extensibly, thereby allowing the absorbent core web 28 toswell. The first web 22 and the second web 30 may suitably be composedof a material which is either liquid permeable or liquid impermeable. Itis generally desirable that at least one of the first web 22 and thesecond web 30 be formed from a material which is substantially liquidpermeable. The liquid permeability may be inherent in the first web 22and/or the second web 30, such as in the example of a low basis weightspunbond. Alternatively, the permeability may result from the first web22 and/or the second web 30 that is inherently liquid impermeable, suchas in the example of a film, which has been modified to provide thepermeability, for example by aperturing.

Other suitable materials for the first web 22 and/or the second web aredescribed in commonly assigned U.S. patent application Ser. No.11/020842 to Abuto et al., entitled, “Stretchable Absorbent Core andWrap,” filed Dec. 21, 2004, the entirety of which is incorporated hereinby reference to the extent that it is consistent (i.e., not in conflict)herewith. The first web 22 and/or the second web 30 may be manufacturedby any suitable means, such as, for example the processes described inU.S. Pat. No. 5,458,592 to Abuto et al. and issued Oct. 17, 1995, theentirety of which is incorporated herein by reference to the extent thatit is consistent (i.e., not in conflict) herewith.

In some embodiments, the absorbent composite web 32 may be separatedinto discrete absorbent composites 90 by any suitable means, such as,for example, rotary cutters, high pressure water cutters, die cutters,saw cutters, and the like. The separation of the absorbent composite web32 into discrete absorbent composites 90 includes the separation of thefirst web 22 into discrete first sheets 92 and the second web 30 intodiscrete second sheets 93. As discussed herein, the absorbent core maybe formed as a continuous absorbent core web 28 and cut into discreteabsorbent cores 91 or may be formed as discrete absorbent cores 91.Therefore, the separation of the absorbent composite web 32 intodiscrete absorbent composites 90 may or may not require the separationof the absorbent core web 28 into discrete absorbent cores 91.

Referring now to FIGS. 7 and 8, the discrete absorbent composite 90 ofthe present invention is representatively illustrated as part of a babydiaper. The baby diaper is indicated in its entirety by the referencenumeral 120. The diaper 120 can suitably be disposable, which refers toarticles that are intended to be discarded after a limited period of useinstead of being laundered or otherwise conditioned for reuse. It shouldalso be understood that the absorbent composite 90 of the presentinvention is suitable for use with various other absorbent articlesintended for personal wear, including, but not limited to, children'straining pants, feminine hygiene products, incontinence products,medical garments, surgical pads and bandages, other personal care orhealth care garments, and the like, without departing from the scope ofthe present invention.

By way of illustration only, various materials and methods forconstructing diapers such as the diapers 120 of the various aspects ofthe present invention are disclosed in U.S. patent application Ser. No.10/836490, filed Apr. 29, 2004, in the name of Schlinz et al.; U.S. Pat.No. 5,496,298 issued Mar. 5, 1996, to Kuepper et al.; U.S. Pat. No.4,798,603 issued Jan. 17, 1989, to Meyer et al.; U.S. Pat. No. 5,176,668issued Jan. 5, 1993, to Bernardin; U.S. Pat. No. 5,192,606 issued Mar.9, 1993, to Proxmire et al., and U.S. Pat. No. 5,509,915 issued Apr. 23,1996, to Hanson et al., each of which are incorporated herein byreference to the extent that they are consistent (i.e., not in conflict)herewith.

The diaper 120 is illustrated in FIG. 7 in a fastened condition. Thediaper 120 is illustrated in FIG. 8 in a laid flat and unfastenedcondition with portions cut away to illustrate underlying detail. Thediaper 120 defines a longitudinal direction 146 and a lateral direction148 perpendicular to the longitudinal direction as shown in FIG. 8. Thediaper 120 further defines a pair of longitudinal end regions, otherwisereferred to herein as a front waist region 122 and a back waist region124, and a center region, otherwise referred to herein as a crotchregion 126, extending longitudinally between and interconnecting thefront and back waist regions 122, 124. The front and back waist regions122,124 include those portions of the diaper 120, which, when worn,wholly or partially cover or encircle the waist or mid-lower torso ofthe wearer. The crotch region 126 generally is that portion of thediaper 120 which, when worn, is positioned between the legs of thewearer and covers the lower torso and crotch of the wearer. The diaper120 also defines an inner surface 128 adapted to be positioned towardthe wearer, and an outer surface 130 opposite the inner surface. Withadditional reference to FIG. 8, the diaper 120 has a pair of opposedarticle side edges 136 extending in the longitudinal direction 146 and apair of opposed article waist edges 138 extending in the lateraldirection 148, referred to herein as the article back waist edge and thearticle front waist edge.

The illustrated diaper 120 can include an absorbent chassis, generallyindicated at 132. The absorbent chassis 132 can define a first chassisside edge 190 extending in the longitudinal direction 146 and a secondchassis side edge 191 extending in the longitudinal direction 146,opposite the first chassis side edge 190. The absorbent chassis 132 canalso define a pair of longitudinally opposite chassis waist edgesreferred to herein as the chassis back waist edge 192 and the chassisfront waist edge 194.

For example, in the aspect of FIGS. 7 and 8, the diaper 120 includes anabsorbent chassis 132 and a pair of ears 134 formed separately from andattached to the absorbent chassis 132 proximate the first chassis sideedge 190 and the second chassis side edge 191. The ears 134 can beattached along seams 156 proximate the chassis side edges 190, 191 ineither the front waist region 122 or in the back waist region 124 of thediaper 120. In the illustrated aspects, the ears 134 are attached in theback waist region 124. The ears 134 may be attached to the absorbentchassis 132 using means known to those skilled in the art such asadhesive, thermal bonding, pressure bonding, ultrasonic bonding, and thelike, or combinations thereof. In alternative embodiments, the ears 134may be formed as an integral part of the absorbent chassis 132. The ears134 may also include fasteners 160, as are known in the art, adapted toreleasably secure the diaper 120 about the waist of the wearer.

The absorbent chassis 132 is illustrated in FIG. 8 as beingsubstantially I-shaped. However, it is contemplated that the absorbentchassis 132 may have other shapes (e.g., hourglass, T-shaped,rectangular, and the like) without departing from the scope of thisinvention.

The absorbent chassis 132 can include an outercover 140 and a bodysideliner 142 in a superposed relation therewith. The liner 142 can besuitably joined to the outercover 140 along at least a portion of theabsorbent chassis 132. The liner 142 can be suitably adapted, i.e.,positioned relative to the other components of the diaper 120, tocontact the wearer's skin during wear of the diaper. The absorbentchassis 132 may also include the absorbent composite 90 disposed on theinner surface of the article relative to the outercover 140 forabsorbing liquid body exudates. For example, the absorbent composite 90can be located between the outercover 140 and the bodyside liner 142.The bodyside liner 142 and the outercover 140 can be attached to eachother by adhesive, ultrasonic bonding, thermal bonding or by othersuitable attachment techniques known in the art. Moreover, at least aportion of the absorbent composite 90 can optionally be attached to thebodyside liner 142 and/or the outercover 140 utilizing the methodsdescribed above. The liner 142 can be coextensive with the outercover140 or can be larger or smaller than the outercover 140.

As discussed herein, the discrete absorbent composite 90 includes afirst sheet 92 and a second sheet 93 joined together at a plurality ofbond points 45. The absorbent core 91 is located between the first andsecond sheets 92 and 93 and the bond points 45 extend through the holes41 within the absorbent core 91.

The diaper 120 can optionally include a pair of containment flaps 155for inhibiting the lateral flow of body exudates. The containment flaps155 can be operatively attached to the diaper 120 in any suitable manneras is well known in the art. In particular, suitable constructions andarrangements for the containment flaps are generally well known to thoseskilled in the art and are described in U.S. Pat. No. 4,704,116 issuedNov. 3, 1987, to Enloe, which is incorporated herein by reference to theextent that it is consistent (i.e., not in conflict) herewith.

To further enhance containment and/or absorption of body exudates, thediaper 120 may optionally include waist elastic members 154 in the frontand/or back waist regions 122 and 124 of the diaper 120. Likewise, thediaper 120 may optionally include leg elastic members 158, as are knownto those skilled in the art. The waist elastic members 154 and the legelastic members 158 can be formed of any suitable elastic material thatis well known to those skilled in the art. For example, suitable elasticmaterials include sheets, strands or ribbons of natural rubber,synthetic rubber, or thermoplastic elastomeric polymers. In one aspectof the invention, the waist elastics and/or the leg elastics may includea plurality of dry-spun coalesced multi-filament spandex elastomericthreads sold under the trade name LYCRA and available from Invista ofWilmington, Del., U.S.A.

The outercover 140 may suitably include a material that is substantiallyliquid impermeable. The outercover 140 may be provided by a single layerof liquid impermeable material, or more suitably include a multi-layeredlaminate structure in which at least one of the layers is liquidimpermeable. In-particular aspects, the outer layer may suitably providea relatively cloth-like texture to the wearer. A suitable liquidimpermeable film for use as a liquid impermeable inner layer, or asingle layer liquid impermeable outercover 140 is a 0.025 millimeter(1.0 mil) polyethylene film commercially available from Edison PlasticsCompany of South Plainfield, N.J., U.S.A. Alternatively, the outercover140 may include a woven or nonwoven fibrous web layer that has beentotally or partially constructed or treated to impart the desired levelsof liquid impermeability to selected regions that are adjacent orproximate the absorbent body.

The outercover 140 may also be stretchable, and in some aspects it maybe elastomeric. For example, such an outercover material can include a0.3 osy polypropylene spunbond that is necked 60 percent in the lateraldirection, creped 60 percent in the longitudinal direction, andlaminated with 3 grams per square meter (gsm) Bostik-Findley H2525Astyrene-isoprene-styrene based adhesive to 8 gsm PEBAX 2533 film with 20percent TiO₂ concentrate. Reference is made to U.S. Pat. No. 5,883,028,issued to Morman et al., U.S. Pat. No. 5,116,662 issued to Morman andU.S. Pat. No. 5,114,781 issued to Morman, all of which are herebyincorporated herein by reference, for additional information regardingsuitable outercover materials.

The bodyside liner 142 is suitably compliant, soft-feeling, andnon-irritating to the wearer's skin. The bodyside liner 142 is alsosufficiently liquid permeable to permit liquid body exudates to readilypenetrate through its thickness to the absorbent composite 90 and theabsorbent core 91 located therein. A suitable liquid permeable bodysideliner 142 is a nonwoven polyethylene/polypropylene bi-component webhaving a basis weight of about 27 gsm; the web may be spunbonded or abonded carded web. Optionally, the bodyside liner 142 may be treatedwith a surfactant to increase the wettability of the liner material.

Alternatively, the bodyside liner 142 may also be stretchable, and insome aspects it may be elastomeric. For instance, the liner 142 can be anonwoven, spunbond polypropylene fabric composed of about 2 to 3 denierfibers formed into a web having a basis weight of about 12 gsm which isnecked approximately 60 percent. Strands of about 9 gsm KRATON G2760elastomer material placed eight strands per inch (2.54 cm) can beadhered to the necked spunbond material to impart elasticity to thespunbond fabric. The fabric can be surface treated with an operativeamount of surfactant, such as about 0.6 percent AHCOVEL Base N62surfactant, available from ICI Americas, a business having offices inWilmington, Del., U.S.A. Other suitable materials may be extensiblebiaxially stretchable materials, such as a neck stretched/crepedspunbond. Reference is made to U.S. Pat. No. 6,552,245, issued Apr. 22,2003, to Roessler et al., which is incorporated by reference herein tothe extent that it is consistent (i.e., not in conflict) herewith.

The absorbent core 91 includes absorbent material 26 and is suitablycompressible, conformable, and capable of absorbing and retaining liquidbody exudates released by the wearer. For example, the absorbent core 91can include a matrix of absorbent fibers, and more suitably cellulosicfluff, such as wood pulp fluff, and superabsorbent particles. Onesuitable pulp fluff is identified with the trade designation CR1654,commercially available from U.S. Alliance, Childersburg, Ala., U.S.A. Asan alternative to wood pulp fluff, synthetic fibers, polymeric fibers,meltblown fibers, short cut homofil bicomponent synthetic fibers, orother natural fibers may be used. Suitable superabsorbent materials canbe selected from natural, synthetic, and modified natural polymers andmaterials. The superabsorbent materials can be inorganic materials, suchas silica gels, or organic compounds, such as cross linked polymers, forexample, sodium neutralized polyacrylic acid. Suitable superabsorbentmaterials are available from various commercial vendors, such as DowChemical Company of Midland, Mich., U.S.A., and Stockhausen Inc.,Greensboro, N.C., U.S.A.

In various embodiments, the absorbent core 91 may include 30 to 90percent superabsorbent by weight. In some embodiments, the absorbentcore 91 may include at least 50, at least 60, at least 70, or at least80 percent superabsorbent by weight. In various embodiments, theabsorbent core 91 may include 70 to 10 percent cellulose fluff byweight. In some embodiments, the absorbent core 91 may include less than70, less than 60, less than 50, less than 40, less than 30, or less than20 percent cellulose fluff by weight. In some embodiments, the absorbentcore 91 may include 50 to 90 percent superabsorbent material by weightand 50 to 10 percent cellulose fluff by weight. In some embodiments, theabsorbent core 91 may include 60 to 90 percent superabsorbent materialby weight and 40 to 10 percent cellulose fluff by weight. In someembodiments, the absorbent core 91 may include 70 to 90 percentsuperabsorbent material by weight and 30 to 10 percent cellulose fluffby weight.

The absorbent core 91 and/or the absorbent composite 90 may have avariety of shapes and configurations as are known in the art, such asrectangular, hourglass shaped, I-shaped, and the like. The absorbentcore 91 may have the same shape or a different shape than the absorbentcomposite 90. For example, the absorbent core 91 may have a rectangularshape and the absorbent composite 90 may have a rectangular shape. Inanother example, the absorbent core 91 may have an hourglass shape andthe absorbent composite 90 may have a rectangular shape.

In some embodiments, the portions of the absorbent composite 90including the absorbent core 91 may have a density within the range ofabout 0.10 to about 0.5 grams per cubic centimeter. The absorbent core91 of the present invention may have a uniform density. In other words,the portions of the absorbent core 91 proximate the holes 41 may haveessentially the same density as the portions of the absorbent core 91more distant from the holes 41. This uniform density is believed toprovide for a soft and conforming absorbent composite 90 without hardspots or hard lines in the product.

Traditional cellulose fluff based absorbent products have been madethinner by greater compression resulting in higher densities and lessflexibility. Alternatively, thinner absorbent products have been madewith less absorbent material but may not have the absorbent capacitynecessary to meet the needs of the wearer. However, as higherconcentrations of superabsorbent materials have become more prevalent,thinner absorbent articles with adequate absorbent capacity have beenmanufactured. Unfortunately, absorbent articles with high concentrationsof superabsorbent material have also traditionally suffered fromstructural breakdowns, superabsorbent shifting, and superabsorbentmigration because the relative percentage of cellulose fluff “holding”the superabsorbent in place has decreased relative to the superabsorbentmaterial contained therein.

In general, the method and apparatus of the present invention iscompatible with relatively thin absorbent cores 91. For example, invarious embodiments, the absorbent core 91 and/or absorbent composite 90can have a thickness of about 1 mm to about 10 mm. In some embodiments,the absorbent core 91 and/or the absorbent composite 90 may have athickness of less than about 9 mm, less than about 8 mm, less than about7 mm, less than about 6 mm, less than about 5 mm, less than about 4 mm,less than about 3 mm, or less than about 2 mm. The thin absorbent core91 of the present invention allows for a thinner absorbent article. Thinabsorbent articles are generally believed to be well suited for comfortand discretion. As used herein, the thickness of the absorbent composite90 describes the thickness as measured in those portions including theabsorbent core 91. One skilled in the art will appreciate that portionsof the absorbent composite 90 may not include the absorbent core 91 (forexample, the marginal areas 42) and would obviously be thinner at theselocations.

The present invention includes a thin absorbent composite having astabilized absorbent core wherein structural breakdowns, superabsorbentshifting, and superabsorbent migration are believed to be limited. Thestabilized absorbent composites include a first sheet joined to a secondsheet at a plurality of bond points corresponding with a plurality ofholes located within an absorbent core. FIG. 9 representativelyillustrates an exemplary absorbent composite 90. Portions of theabsorbent composite 90 are cut away in FIG. 9 to illustrated underlyingfeatures. FIG. 10 representatively illustrates the portion of FIG. 9delineated by box 10 and magnified for clarity and with portions cutaway to illustrate underlying details. FIG. 11 is a cross sectional viewof the portion of the absorbent composite 90 illustrated in FIG. 10.

Referring now to FIGS. 9,10 and 11, the absorbent composite 90 includesa first sheet 92, a second sheet 93, and a discrete unitary absorbentcore 91 located therebetween. The absorbent core 91 has a plurality ofholes 41 extending there through and is positioned between the firstsheet 92 and the second sheet 93. The first sheet 92 extends through theholes 41 in the absorbent core 91 and is joined with the second sheet 93at a plurality of bond points 45. The plurality of bond points 45stabilize the absorbent core 91 and the absorbent composite 90.Therefore, the resulting absorbent composite 90 includes a stabilizeddiscrete unitary absorbent core 91 that is believed to be thin, soft,and compliant having no ridges, hard lines, or hard spots.

The unitary absorbent cores of the present invention have overall“continuity” (i.e., no segmenting) and are believed to promote freefluid movement throughout the entire core. The bond points are believedto improve the integrity of the absorbent composite, but the relativelysmall holes maintain a large absorbent area available to receiveinsults. Additionally, it is believed that the unitary absorbent coreswith uniform densities will bend continuously and evenly about thewearer. Finally, it is believed that unitary absorbent cores willdistribute the weight of the wearer more evenly and won't result inpressure points possible with discontinuous absorbent cores.

The holes 41 in the absorbent core 91 may have any suitable shape andany suitable size. For example, the holes 41 may have a circular shape,as illustrated in FIG. 9, but may alternatively be in the shape of anoval, square, triangle, or any other suitable geometric shape,irregular, or the like, or combinations thereof. In some embodiments,the absorbent cores 91 may have at least one first hole having a firstshape and at least one second hole having a second shape wherein thefirst shape and the second shape are different. In some embodiments, theabsorbent cores 91 may have at least one first hole having a first sizeand at least one second hole having a second size wherein the lo firstsize and the second size are different.

In various embodiments, the holes 41 may have a hole area 171 of 1 mm²(0.0015 in²) to 200 mm² (0.3 in²), 1 mm² (0.0015 in²) to 100 mm² (0.155in²), or 1 mm² (0.0015 in²) to 25 mm² (0.03875 in²). In someembodiments, the hole area 171 may be less than 200 mm², less than 100mm², less than 90 mm², less than 80 mm², less than 70 mm², less than 60mm², less than 50 mm², less than 40 mm², less than 30 mm², less than 20mm², or less than 10 mm². In embodiments wherein the holes 41 have agenerally circular shape, the holes 41 may have a diameter of 1 mm to 16mm, 1 mm to 10 mm, or 1 mm to 5 mm. In some embodiments the holes 41 mayhave a diameter of less than 16 mm, less than 10 mm, or less than 5 mm.In various embodiments, the total area of the holes 41 may be betweenabout 1 to about 33 percent, about 1 to about 25 percent, or less thanabout 10 percent of the total area of the absorbent core 91.

In various embodiments, the absorbent cores may have at least one firsthole having a first hole area and at least one second hole having asecond hole area wherein the first and second hole areas are different.For example, in some embodiments, the absorbent cores may define a frontportion generally oriented towards the front waist region of theabsorbent article and a back portion generally oriented towards the backwaist region of the absorbent article wherein the back portion includesholes having a larger hole area and wherein the front portion includesholes having a smaller hole area.

The absorbent material surrounding the holes 41 defines a hole wall 175.The hole wall 175 is preferably no more or less dense than any otherportion of the absorbent core 91 which is believed to be morecomfortable to the wearer. In contrast, some traditional methods ofstabilizing absorbent cores, such as pin aperturing, embossing,needling, and the like, have resulted in densified regions surroundingindentations. Such densifications may impact fluid movement within theabsorbent core, may be noticeable to a wearer and/or caregiver, and mayreduce the flexibility of the absorbent core 91.

The bonds 45 may be any suitable shape and any suitable size. Forexample, the bonds 45 may be circular, as illustrated in FIG. 10, butmay also be oval, square, triangular, or any other suitable geometricshape, irregular, or the like, or combinations thereof. In someembodiments, the absorbent cores 91 may have at least one first bondhaving a first shape and at least one second bond having a second shapewherein the first shape and the second shape are different. In someembodiments, the absorbent cores 91 may have at least one first bondhaving a first size and at least one second bond having a second sizewherein the first size and the second size are different.

In some embodiments, the bonds 45 may have a bond area 173 of 1 mm²(0.0015 in²) to 200 mm² (0.3 in²), 1 mm² (0.0015 in²) to 100 mm² (0.155in²), or 1 mm² (0.0015 in²) to 25 mm² (0.03875 in²). In someembodiments, the bond area 173 may be less than 200 mm², less than 100mm², less than 90 mm², less than 80 mm², less than 70 mm², less than 60mm², less than 50 mm², less than 40 mm², less than 30 mm², less than 20mm², or less than 10 mm². In embodiments wherein the bonds 45 generallyhave a circular shape, the bonds 45 may have a diameter of 1 mm to 16mm, 1 mm to 10 mm, or 1 mm to 5 mm. In some embodiments the bonds 45 mayhave a diameter of less than 16 mm, less than 10 mm, or less than 5 mm.

In various embodiments, the absorbent cores 91 may have at least onefirst bond having a first bond area and at least one second bond havinga second bond area wherein the first and second bond areas aredifferent. For example, in some embodiments, the absorbent cores maydefine a front portion generally oriented towards the front waist regionof the absorbent article and a back portion generally oriented towardsthe back waist region of the absorbent article wherein the back portionincludes bonds having a larger bond area and wherein the front portionincludes bonds having a smaller bond area.

In some embodiments, larger bonds and smaller bonds may be intermixedthroughout the absorbent core in any suitable arrangement. In someembodiments, smaller bonds may be adapted to release when the absorbentmaterial is wetted. In some embodiments, larger bonds may be adapted toremain joined when the absorbent material is wetted.

In some embodiments, the bond area 173 is at least 60, 70, 80, 90, or 95percent that of the hole area 171, resulting in an unbonded area 177that is less than 40, 30, 20, 10, or 5 percent of the hole area 171. Itis believed that having the bond area 173 close to the same size as thehole area 171 results in greater stabilization of the absorbent core 91because less of the absorbent material 26 is unsupported, i.e., there isless unbonded area 177. For example, as illustrated in FIG. 10, the bondarea 173 is approximately 60 percent of the hole area 171, whereas theunbonded area 177 is about 40 percent of the hole area 171.

In some embodiments, the bond area 173 may be substantially devoid ofabsorbent material 26. In other words, the first sheet 92 may be joineddirectly to the second sheet 93 at the bond points 45 with substantiallyno absorbent material 26 therebetween. In some embodiments, the bondarea 173 may be free of absorbent material 26. In other words, the firstsheet 92 may be joined directly to the second sheet 93 at the bondpoints 45 with no absorbent material 26 therebetween as illustrated inFIG. 11.

As illustrated in FIG. 11, the bonds 45 are skewed towards the secondsheet 93. As such, the first sheet 92 extends at least partially throughthe holes 41 of the absorbent core 91. In some embodiments, the firstsheet 92 extends entirely through the holes 41 of the absorbent core 91.In one embodiment, the first sheet 92 may be positioned towards theliner 142 and the second sheet 93 may be oriented towards the outercover140. In another embodiment, the second sheet 93 may be positionedtowards the liner 142 and the first sheet 92 may be oriented towards theoutercover 140.

In various embodiments, the bonds 45 may be generally located within theholes 41. In some embodiments, the bonds 45 may be registered within theholes 41. In other words, the bonds 45 may be generally centered withinthe holes 41. For a bond 45 to be generally centered within the hole 41means that the bonds 45 have a center point and the holes 41 have acenter point and both center points coincide at common center point 179as illustrated in FIG. 10. In some embodiments, at least 60, at least70, at least 80, at least 90, and at least 99 percent of the bonds 45are located with the holes 41. In some embodiments, 100 percent of thebonds 45 are located within the holes 41. In some embodiments, at least60, at least 70, at least 80, at least 90, and at least 99 percent ofthe bonds 45 are registered within the holes 41. In some embodiments,100 percent of the bonds 45 are registered within the holes 41.

In various embodiments, the absorbent composite may have a “bond pointdensity” of 0.05 to 1.0 bond points 45 per square centimeter ofabsorbent core 91. In some embodiments, the absorbent composite may have0.1 to 0.5 bond points 45 per square centimeter of absorbent core 91. Insome embodiments, the absorbent composite may have 0.2 to 0.4 bondpoints 45 per square centimeter of absorbent core 91. In someembodiments, the absorbent core 91 may have a first bond point densityin a first region and a second bond point density in a second region.For example, the absorbent core 91 may have a front portion locatedgenerally towards the front waist region of the absorbent article and aback portion located generally towards the back waist region of theabsorbent article wherein the front portion has a higher density of bondpoints and the back portion has a lower density of bond points. In someembodiments, the bond points 45 may have a diameter, D, and may bespaced apart by at least one times, two times, three times, or more thanfour times the diameter, D.

In various embodiments, the absorbent composite 90 may include anabsorbent core 91 located between a liquid pervious first sheet 92 and aliquid pervious second sheet 93. The liquid pervious first sheet 92extends through holes 41 in the absorbent core 91 to join with theliquid pervious second sheet 93 at a plurality of bond points 45. Invarious embodiments, the absorbent composite 90 may include an absorbentcore 91 located between a liquid impervious first sheet 92 and a liquidpervious second sheet 93. The liquid impervious first sheet 92 extendsthrough holes 41 in the absorbent core 91 to join with the liquidpervious second sheet 93 at a plurality of bond points 45. In variousembodiments, the absorbent composite 90 may include an absorbent core 91located between a liquid pervious first sheet 92 and a liquid impervioussecond sheet 93. The liquid pervious first sheet 92 extends throughholes 41 in the absorbent core 91 to join with the liquid impervioussecond sheet 93 at a plurality of bond points 45. In variousembodiments, the first sheet 92 or the second sheet 93 may face towardsthe liner 142.

In one aspect, the absorbent composite 90 may be stretchable so as notto inhibit the stretchability of other components to which the absorbentcomposite 90 may be adhered, such as the outercover 140 and/or thebodyside liner 142. For example, the absorbent composite 90 may includematerials disclosed in U.S. Pat. Nos. 5,964,743, 5,645,542, 6,231,557,6,362,389, and international patent application WO 03/051254, thedisclosure of each of which is incorporated by reference herein to theextent that they are consistent (i.e., not in conflict) herewith.

In some aspects, a surge management layer (not shown) may be included inthe diaper 120. The surge management layer may be positioned in thediaper 120 in a variety of locations as is known in the art. Forexample, the surge management layer can be proximate the absorbentcomposite 90, for example between the absorbent composite 90 and thebodyside liner 142, and attached to one or more components of the diaper120 by methods known in the art, such as by adhesive, ultrasonicbonding, pressure bonding, thermal bonding, and the like, orcombinations thereof.

A surge management layer helps to decelerate and diffuse surges orgushes of liquid that may be rapidly introduced into the absorbentcomposite 90. Desirably, the surge management layer can rapidly acceptand temporarily hold the liquid prior to releasing the liquid into thestorage or retention portions of the absorbent composite 90. Examples ofsuitable surge management layers are described in U.S. Pat. No.5,486,166 and U.S. Pat. No. 5,490,846, the contents of which areincorporated herein by reference to the extent that they are consistent(i.e., not in conflict) herewith.

While the invention has been described in detail with respect tospecific embodiments thereof, it will be appreciated that those skilledin the art, upon attaining understanding of the foregoing will readilyappreciate alterations to, variations of, and equivalents to theseembodiments. Accordingly, the scope of the present invention should beassessed as that of the appended claims and any equivalents thereto.

1. A method for forming and stabilizing an absorbent composite web,comprising, conforming a first web onto a forming surface having aplurality of raised nubs having upper surfaces, the first web defining aplurality of bond areas corresponding to those portions of the first weboverlying the upper surfaces of the nubs, depositing absorbent materialonto the first web to form a unitary absorbent core having a pluralityof holes therein, joining a second web to the first web at the bondareas to form an absorbent composite web, wherein the unitary absorbentcore is positioned between the first web and the second web, and thefirst web and the second web are bonded together through the holes inthe absorbent core, and removing the absorbent composite web from theforming surface.
 2. The method of claim 1 further comprising applyingadhesive to the second web before joining the second web to the firstweb.
 3. The method of claim 2 further comprising pressing the second webagainst the first web while the first web is conformed to the formingsurface to effectuate the joining of the second web to the first web. 4.The method of claim 1 wherein the joining step includes ultrasonicbonding, thermal bonding, or pressure bonding.
 5. The method of claim 1wherein the first web is drawn to the forming surface via vacuum forcesand the forming surface is a drum former.
 6. The method of claim 1wherein the nubs have a height of 1.5 to 6 mm and a surface area of 1 to25 mm².
 7. The method of claim 1 wherein the absorbent material includessuperabsorbent particles and cellulose fluff fibers.
 8. The method ofclaim 7 wherein the unitary absorbent core comprises 30 to 90 percentsuperabsorbent particles and 70 to 10 percent cellulose fluff fibers byweight.
 9. The method of claim 7 wherein portions of the absorbentcomposite web comprising the unitary absorbent core have a thickness ofless than 6 mm.
 10. The method of claim 1 further comprising scarfingthe absorbent core to expose the bond areas before joining the secondweb to the first web.
 11. The method of claim 1 wherein the first weband the second web are tissue webs and the joining includes adhesive.12. The method of claim 1 wherein the first web and the second web arenonwoven webs and the joining includes adhesive bonding, ultrasonicbonding, thermal bonding, or pressure bonding.
 13. A method for formingan absorbent composite web, comprising, conforming a first tissue webonto a forming surface via vacuum forces, the forming surface having aplurality of raised nubs having upper surfaces, the first tissue webdefining a plurality of bonding areas corresponding to those portions ofthe first tissue web overlying the upper surfaces of the nubs,depositing superabsorbent and cellulose fluff onto the first tissue webto form a unitary absorbent core having a plurality of holes therein,applying adhesive to a second tissue web, pressing the second tissue webagainst the first tissue web to join the first and second tissue webs atthe bonding areas to form an absorbent composite web, wherein theunitary absorbent core is positioned between the first tissue web andthe second tissue web and the first tissue web and the second tissue webare bonded together through the holes in the unitary absorbent core, andremoving the absorbent composite web from the forming surface.
 14. Themethod of claim 13 further comprising scarfing the unitary absorbentcore to remove substantially all absorbent material from the bond areas.15. The method of claim 13 wherein the unitary absorbent core comprises30 to 90 percent superabsorbent and 70 to 10 percent cellulose fluff byweight.
 16. The method of claim 13 wherein portions of the absorbentcomposite web comprising the unitary absorbent core have a thickness ofless than 6 mm.
 17. A method for forming an absorbent composite web,comprising, conforming a first nonwoven web onto a forming surface viavacuum forces, the forming surface having a plurality of raised nubshaving upper surfaces, the first nonwoven web defining a plurality ofbond areas corresponding to those area of the first nonwoven weboverlying the upper surfaces of the nubs, depositing superabsorbent andcellulose fluff onto the first nonwoven web to form a unitary absorbentcore, scarfing the absorbent core to remove substantially all absorbentmaterial from the bond areas and to define a plurality of holes in theunitary absorbent core, joining the second nonwoven web to the firstnonwoven web at the bond areas using adhesive bonding, ultrasonicbonding, thermal bonding, or pressure bonding to form an absorbentcomposite web, wherein the unitary absorbent core is positioned betweenthe first nonwoven web and the second nonwoven web and the firstnonwoven web and the second nonwoven web are bonded together through theholes in the unitary absorbent core, and removing the absorbentcomposite web from the forming surface.
 18. The method of claim 17wherein the unitary absorbent core comprises 30 to 90 percentsuperabsorbent and 70 to 10 percent cellulose fluff by weight.
 19. Themethod of claim 17 wherein the absorbent composite web has a thicknessof less than 6 mm.
 20. The method of claim 17 further comprisingseparating the absorbent composite web into discrete absorbentcomposites and placing the discrete absorbent composites between abodyside liner and an outercover to form an absorbent article.